inhibitors of gastric acid secretion Flashcards

1
Q

Antacids are more effective on which kinds of ulcers?

A

Duodenal ulcers
less effective on gastric ulcers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Antacids contain

A

salts of magnesium - magnesiym hydroxide, magnesiym trisilicate
salts of aluminium- aluminium hydroxide gel
combined with alginates and simeticone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

At what stage of development is H. pylori often acquired?

A

During childhood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Bismuth subsalicylate has minimal GI absorption. True or false

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Briefly state the MOA for Misoprostol ;

A

reduce gastric acid secretion
increase mucosal blood flow
secretion of mucous and bicarbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Chief cells produce…

A

Pepsin- breaks down proteins
Lipase- breaks down fats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cimetidine may cause gynaecomastia in men due to …

A

low affinity for androgen receptors
((prevents testoterone from having its effects?)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

D cells in the stomach secrete

A

Somatostatin; inhibits the release of other hormones from cells in the stomach lining

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Excess salts of aluminium can cause _____

A

constipation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Excess salts of magnesium can cause ___

A

diarrhoea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Generally, how can we prevent peptic ulcers

A

lifestle measures
avoid gastric irritants
boost gastric defences
reduce gastric acid secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Give examples of cytoprotective drugs

A

Sucralfate: complex of aluminium hydroxide and sulphated sucrose, releases the aluminium in the presence of acid
Bismuth subsalicylate
Misoprostol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Give exampls of proton pump inhibitors

A

lansoprazole
omeprazole
esomeprazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

H pylori infection is implicated in what instances?

A

causative factor in gastric acid production
peptic ulcers
gastric ulcers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

H. pylori is a gram _____ bacteria found in ____ UK population

A

negative
10-15%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

H. pylori is found in ___ of patients with duodenal cancer

A

80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

H2 receptor antagonists are eliminated by the ____

A

Kidneys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are PPIs adminisitered

A

most commonly orally
omeprazole contains enteric coated granules as degraded quickly at low pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do antacids work?

A

They work by directly neutralising the gastric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do ulcers develop?

A

failure of luminal defences- decrease mucous and HCO3, < protection of mucosa against acidic lumen
failure to inhibity gastric acid secretion; build up of acid damages unprotected mucosa
increased pepsin secretion; proteins break down in unprotected mucosa
increase gastric emptying into duodenum; increased acid reached duodenum causing ulcers
h. pylori infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Infection of H. pylori can lead to the following conditions:

A

Gastritis
Peptic ulcers
Gastric cancers
MALToma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

List some H2 receptor antagonists

A

cimetidine
ranitidine
famotidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Misoprostol limits gastric mucosa damage by NSAIDs and promote ulcer healing. True or false

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Mucous cells of the stomach produce…

A

Mucus (protective layer)
Bicarbonate (mucosal surface pH 6-7; protect mucosal cells from acidic lumen of pH 1-2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Non ulcer dyspepsia (NUD) or functional dyspeptis is characterised by ...
no cause found for symptoms no ulcer increased GI sensitivity to distension Increased GI sensitivity to gastric acid
26
Parietal cells produce...
HCl which is important in proteolytic digestion of food, iron absorption and killing pathogens
27
Peptic ulcer disease is characterised by...
peptic ulcer (break in the lining of stomach, duodenum or lower oesophagus) ulcer in stomach (gastric ulcer) ulcer in duodenum (duodenal ulcer) epigastric pain in upper abdominal region
28
Pharmacologically how can we treat gastric ulcers?
proton pump inhibitors histamine H2 receptor antagonists (act on parietal cells in stomach which release HCl) antacids cytoprotective drugs antibiotics
29
PPIs are eliminated by the ___
Liver
30
Reinfection of the h.pylori organism is not possible after elimination. True or false
False Hence screening is important
31
The eradication of H pylori infection has what effect on ulcers?
promotes rapid and long term healing of ulcers
32
What aggravates a gastric ulcer and what does this lead to
GU is worse with eating and this leads to weight loss
33
What alleviates a duodenal ulcer and briefly explain why
DU is better with eating due to the action of the acid on food
34
What ar the 3 regulatory molceules that stimulate acid secretion
Acetylcholine- M3AChR- parietal cell Histamine- H2R on parietal cells gastrin- released from G cell which act on CCK (cholecytokinin) receptors on ECL (enterochromaffin like cells) which cause the release of histamine (which stimulate HCl)
35
What are cytoprotective drugs
drugs which protect the mucosa by enhancing endogenous mucosal protection provide a physical barried the surface fo the ulcer
36
What are the adverse effects of bismuth subsalicylate
blackening of tongue and faeces nausea and vomiting raised plasma levels during renal impairment can cause encephalopathy
37
What are the adverse effects of H2 receptor antagonists
diarrhoea dizziness muscle pain headache transient rash cimetidine inhibits cytochrome P450 reducing metabolism (this potentiating the action) of other drugs, anticoagulants and tricyclic antidepressants
38
What are the adverse effects of misoprostol
diarrhoea abdominal cramos avoid in pregnancy due to induction of uterine contraciton leading to abortion
39
What are the adverse effects of PPIs
diarrhoea dizziness muscle pain headache rash nausea low Na+ Inhibits enzyme CYP2C19 which is required by clopidogrel to produce the active metabolite (decreasing antiplatelet effect) caution in people with liver disease
40
What are the adverse effects of sucralfate
given orally, poor GI absorption; in an acid environment it produces a paste which can become an obstructive lump (Bezoar), leading to constipation reduces absorption of fluoroquinoine antibiotics, theophylline, tetracycline, digoxin, amitriptyline
41
What are the adverse side effects of antacids?
constipation flatulence systemic alkalosis metabolic bone disease (aluminium) drug interactions- bind to and reduce the effects of tetracycline (antibiotic)
42
What are the complacations of peptic ulcers
slow or fast bleeding- leads to anaemia perforating (in stomach wall) peritonitis (inflammation of the peritoneum) septicaemia (blood poisoning and infection) scarring- gastri outlet obstruction death
43
What are the cytoprotective effects of prostaglandincs PGE2 and PGI2?
decrease gastric secretion increase gastric mucous secretion increase HCO3 secretion prevent vasoconstricion, thus prevent damage to the mucosa following injury (encourage blood flow)
44
What are the protective mechaninsm in place in the stomach used to prevent gastric mucosal injury?
Mucous layer with HCO3; protects the mucosal cells from acidic lumen (pH 1-2) Prostaglandins (local hormones)- produced by most cells in GI tract Cell renewal; every 4-6 days, replace damaged cells Tight cell junctions- prevent acid from seeping into deeper layers
45
What are the risk factors for peptic ulcers
smoking excess alcohol NSAIDs physoological stresses gender: DU more common than GU in females
46
What is an indication for misopriostol
deficiency in endogenous prostaglandin when NSAIDs may cause ulcer formation
47
What is dyspepsia
a condition characterised by upper abdomina symptoms that include pain or discomfort, bloating, feeling of fullness with very little intake of food, feeling of unusual fulless following meals, nausea and vomiting, loss of appetite, heartburn, regurgitation of food or acid and belching
48
What is gynaecomastia?
increase in the amount of breast gland tissue in men/boys
49
What is misoprostol
prostaglandin analogue (PGE1 and PGI2)
50
What is the function of alginates in antacids
increase viscocity and adherence of mucous to oesophagus (protective barrier during reflux)
51
What is the function of simeticone in antacids
antifoaming agentm relieves bloating and flatulence
52
What is the half-life of PPIs
1 hour but a single dose can affect secretion for 2-3 days as it irreversibly blocks the proton pump
53
What is the mechanism of action of H.pylori
penetrates the mucous lining produces an enzyme called urease urease catalyses the hydrolysis of urea into carbondioxide and ammonia ammonia is toxic to mucosal epithelial cells and neutralises pH at mucosa, allowing survival of bacteria
54
What is the mechanism of action of H2 receptor antagonists
inhibits H2 receptors on parietal cells inhibit histamine and gastrin stimulated acid secretion (and pepsin release) promote healing of gastric ulcers
55
What is the mechanism of action of proton pump inhibitors
inhibits K+, H+ ATPase proton pump on parietal cells which reduces acid secretion
56
What is the mechanism of action of sucralfate
the residual anionic complex binds to cationic glycoproteins/proteins in mucous and decreased their degradtion by pepsin stimulates secretion of mucous, bicarbonate, and prostaglandins from gastric mucoisa (increasing the protective layer)
57
What is the MOA of bismuth subsalicylate
precipitates in acidic pH and binds to the ulcer base when used in combination H. pylorin regimens, it has a toxic effect on the bacillus by inhibiting bacterial adherence to the mucosal inhibit the bacterial enzymes
58
What is the one regulatory molecule that inhibits acid secretion?
Somatostatin Released from D cells and acts on G cells, ECL cells and parietal cells to inhibit gastrin, histamine and HCl secretion respectively
59
What leads to the pathogenesis often observed in gastric mucosal injurt
Disturbance in protective mechanisms and excessive gastric secretions
60
What method of administration is available for H2 receptor antagonists
orally (well absorbed by GI tract) IM and IV preparations available low dose over the counter available
61
What type of drugs provide th simplest way to treat symptoms of excessive gastic acid secretion, provide quick relief and have a prolonged effect after food?
antacids
62
Why are NSAIDs like aspirin a risk factor for peptic ulcers
they are acidic molecules which directly irritate gastric mucosa inhibition of COX-1 and 2 which reduces the levels of protective prostaglandins
63
With a positive h. pylori test, the organism can be eradicated in 2 weeks using what kind or therapy
triple therapy: PPI ( decrease gastric acid secretion) anti-bacterials (amoxicillin, clarithomycin/metronidazole) bismuth subsalicylate (cytoprotective drug- prevent adhesion to mucosa and inhibits the bacterial enzymes